1. Field of the Invention
This invention relates to a recessed lighting fixture that is easier to install, has fewer parts, better optics, and is more readily accessible for adjustment, alteration, and inspection than conventional fixtures. More particularly, this fixture is especially adapted for ceiling installation.
2. The State of the Art
As a brief retrospective of indoor lighting, the standard incandescent light bulb, generally known as an "A-type" bulb, is held in a socket through which electricity is supplied to the bulb. As now typically standardized, the bulb is secured with metal threads on the end of the bulb electrically connecting with the threaded socket. Over time it was appreciated that a naked light bulb was not only unattractive but also inefficient in distributing light; that is, because light radiates essentially spherically from the filament in an A-type bulb, light emanating towards the ceiling is not useful for providing light to the environment. Accordingly, various types of shades, reflectors, and other adapters were devised in combination with the socket in attempts to provide the desired lighting of the environment.
Later developments led to an incandescent bulb having an internal reflector. In essence, a portion of the inside of the bulb is coated with a reflective material so that light from the filament is emitted in one direction and light emitted in the other direction is reflected such that it too emanates in the desired direction. The need for a separate reflector to redirect the light was eliminated by making the bulb into a directional light source. These are commonly known today as R and PAR type bulbs.
Both A-type, PAR, and R types of bulbs are used in ceiling mounted lighting fixtures. The typical ceiling mounted lighting fixture is comprised of a frame with some means for being secured to the structural supports of the ceiling, generally wood joists. In a typical installation where ceiling tiles or gypsum boards form the ceiling structure, the frame of the lighting fixture includes holes or brackets though which fasteners are used to securely position and attach the fixture to the joists supporting the ceiling. In the so-called hung, drop, or suspended ceiling installations, a metal gridwork is suspended in spaced relation to the overhead structure. In this environment, the frame of the lighting fixture is provided with guideways or similar means for interconnection with the grid components for supporting the fixture at a desired position on the grid. With these typical ceiling installations, the installer has access to the structural members from which the ceiling is hung and is readily able to attach the lighting fixture to those structural elements.
Depending upon building codes and architectural needs and desires, the ceiling environment may be insulated or non-insulated (referred to as IC or non-IC, "IC" being an abbreviation for "insulated ceiling"). The design environment determines whether the lighting fixture must be an IC or non-IC type of fixture for electrical and thermal safety considerations. A ceiling that is insulated will retain heat generated by a bulb in the lighting fixture. Accordingly, the fixture and its vicinity can become quite hot. An IC fixture, because it is designed to operate at higher temperatures found in an insulated ceiling, is used in an insulated ceiling and also can be used in a cooler, non-IC environment. A non-IC fixture can be used safely only where insulation is not present.
Another important aspect of the propriety of an IC or non-IC design for the specific lighting fixture application depends upon the bulb used in the fixture. Use of an improper type or wattage of bulb can create hazards, such as a temperature higher than the fixture (and possibly the insulation) is able to accomodate for the specific environment. As will be described in more detail later, conventional lighting fixtures include a partial reflector that obfuscates or otherwise covers the instructions for which type of bulb is appropriate. Unless these instructions are readily visible when changing the bulb, it becomes more likely that one might inadvertently use an improper bulb, creating a potentially dangerous condition with respect to overloading the electrical circuitry and/or a thermal condition creating a fire hazard.
Another aspect of this type of fixture is the cost savings that might be achieved by a minimal design. Ceiling mounted fixtures are very widely used, in virtually every new construction operation, whether for residential or commercial use. Accordingly, significant costs savings may be achieved by reducing the number and/or weight of the components necessary to provide such a fixture.
Yet another problem with prior art devices is caused by the rigidity of the frame. Although the joists or other ceiling structure to which the lighting fixture is attached are intended to be orthogonal with the plane of the ceiling, a slightly sloped ceiling or installation of the device at a slight slope will prevent the optics from being as desired. The prior art fixtures have a rigid, unchangeable geometry, and so must be mounted with particular care towards their relationship to the ceiling; such customized installation is rare and somewhat contrary to the intended use of mass-produced, easily installed lighting fixtures.
In essence, prior art devices have a number of deficiencies regarding safey and cost of manufacturing. A simpler or more efficient fixture design would not only facilitate installation, but likely would also save manufacturing costs by reducing the number of individual component parts and/or the weight of materials used.